1. Field of the Invention
The present invention relates to an evaluation device and method for providing a transceiver system with performance information thereof, more particularly to an evaluation device and method for providing a transceiver system, which models a channel thereof using Nakagami distribution, with performance information thereof.
2. Description of the Related Art
Referring to FIG. 1, a conventional transceiver system 9 under a transmit antenna selection/maximal-ratio combining (TAS/MRC) scheme includes a transmitter (TX) and a receiver (RX). The transmitter (TX) includes a modulator 91, a diversity unit 93 electrically connected to the modulator 91, and a plurality of transmit antennas 921 electrically connected to the diversity unit 93. The receiver (RX) includes a demodulator 94, a synthesis unit 96 electrically connected to the demodulator 94, and a plurality of receive antennas 951 electrically connected to the synthesis unit 96. The conventional transceiver system 9 is operable, in advance, to estimate the channels between the transmitter (TX) and the receiver (RX), so that the diversity unit 93 of the transmitter (TX) is operable to select one of the transmit antennas 921, which results in a channel that has relatively better performance, for transmitting a signal generated by the modulator 91 so as to optimize the performance of the conventional transceiver system 9. Then, when the receive antennas 951 of the receiver (RX) receive the signal from the selected one of the transmit antennas 921, the synthesis unit 96 of the receiver (RX) is operable to weight and synthesize signals received by the receive antennas 951 thereof.
In “Analysis of Transmit Antenna Selection/Maximal-Ratio Combining in Rayleigh Fading Channels,” IEEE Trans. Veh. Technol., Vol. 54, No. 4, pages 1312-1321, July 2005, Z. Chen et al. propose a method for evaluating performance of the conventional transceiver system 9 by using Rayleigh fading model (see Rayleigh distribution shown in FIG. 2) to simulate the channels of the conventional transceiver system 9. Further, X. Zhang et al. also propose another method for evaluating performance of the conventional transceiver system 9 by using Rayleigh fading model in “Performance Analysis of Multiuser Diversity in MIMO Systems with Antenna Selection,” IEEE Trans. Wireless Commun., Vol. 7, No. 1, pages 15-21, January 2008. However, Rayleigh fading model is only suitable for simulation of the fading simply attributed to multipath propagation, and is inappropriate for simulation of masking, fading, or other interferences in a metropolis. Therefore, a bit error rate (BER) or a symbol error rate (SER), which is computed according to Rayleigh fading model, is not accurate.
In “BER Performance of Transmitter Antenna Selection/Receiver-MRC over Arbitrarily Correlated Fading Channels,” IEEE Trans. Veh. Technol., Vol. 58, No. 6, pages 3088-3092, July 2009, B. Y. Wang and W. X. Zheng introduce a method for evaluating performance of the conventional transceiver system 9 by using Nakagami channel model (see Nakagami distribution shown in FIG. 3) to simulate the channels of the conventional transceiver system 9. Further, the modulator 91 of the conventional transceiver system 9 is configured to perform signal modulation according to binary phase-shift keying (BPSK) modulation. However, the BPSK modulation is merely the simplest form of phase-shift keying (PSK), i.e., a particular example of M-ary phase-shift keying (M-PSK) or M-ary quadrature amplitude modulation (M-QAM) with a power of 2. Therefore, the method proposed by B. Y. Wang and W. X. Zheng for estimating the BER or the SER cannot be used generally when the power of M-PSK or M-QAM is not equal to 2. In addition, this method is merely suitable to the Nakagami channel model associated with integer fading parameters, and the fading parameters are usually non-integer for estimation in a metropolis.
Addressing the drawbacks of the method proposed by B. Y. Wang and W. X. Zheng, there is an improved method for evaluating the SER described in “Performance of Multichannel Reception with Transmit Antenna Selection in Arbitrarily Distributed Nakagami Fading Channels,” J. M. Romero-Jerez et al., IEEE Trans. Wireless Commun., Vol. 8, No. 4, pages 2006-2013, April 2009. The method proposed by J. M. Romero-Jerez et al. is suitable for the Nakagami channel model associated with arbitrary fading parameters, and is generally useful for M-PSK and M-QAM. However, in this method, the SER is computed based upon Lauricella hypergeometric function with a number (LT+1) of variables, where LT is the number of the transmit antennas 921, and thus, the computation of the SER is considerably large.
Further, Z. Chen et al. propose another improved method similar to the method proposed by J. M. Romero-Jerez et al. in “Error Performance of Maximal-Ratio Combining with Transmit Antenna Selection in Flat Nakagami-m Fading Channels,” IEEE Trans. Wireless Commun., Vol. 8, No. 1, pages 424-431, January 2009. In this method, an infinite polynomial with a power of (LT−1) is used for evaluating the conventional transceiver system 9, and thus, the computation of evaluation is also considerably large.